The present invention relates to a heat exchanger, in particular a refrigerant evaporator, of the generic type comprising a plurality of tubular elements assembled to form a stack, wherein each tubular element comprises two pressed plates which enclose between them a cavity Each pressed plate has a pressed-out portion with an orifice therein positioned near at least one end of the tubular element, the pressed-out portion being capable of bearing on the adjacent tubular element and being connected to its cavity via the orifice. Corrugated ribs or fins are arranged between each two adjacent tubular elements.
U.S. Pat. No. 5,176,206 describes a heat exchanger which consists of a multiplicity of flat tubular elements, the tubular elements each being formed from two pressed plates. The tubular elements, with corrugated ribs being interposed, are assembled to form a stack. A side part is arranged at each of the two ends of the stack. The sheet metal plates from which the tubular elements are made have, at one end of their longitudinal extension, pressed-out portions with orifices arranged therein, the pressed-out portions being directed in each case to the adjacent tubular element, so that the tubular elements, succeeding one another in each case, bear with their pressed-out portions against one another. The orifices in the pressed-out portions form passages to the cavity of the next tubular elements in each case, so that a flow duct for the fluid flowing through the heat exchanger is formed.
In the known arrangement, the faces on which two plates forming a tubular element bear against one another in each case are of planar design. The tubular elements in each case adjacent to one another likewise bear with purely planar faces against one another, so that extreme care must be taken with the stack assembled from tubular elements and corrugated ribs, until, after soldering, a displacement of the plates relative to one another is no longer possible. However, such a method of treating a stack consisting of tubular elements cannot be implemented in practice, and therefore complicated fixing and clamping devices are necessary in order to secure the individual plates or tubular elements in their relative position in relation to the arrangement as a whole. However, clamping devices of this type are expensive and impede the production cycle, which is ultimately reflected in the production costs of the heat exchanger.
U.S. Pat. No. 5,086,832 discloses a heat exchanger which consists of stacked tubular elements, each consisting of two pressed plates. In this case, the plates have spacing and interlocking deformations at one end, so that the plates in each case adjacent to one another are fixed at this end to the plate adjacent to them. However, this necessitates corresponding shaping which results in an increased use of material, in an impediment to the production process and in a greater weight of the heat exchanger. Such complicated measures are also ultimately reflected in the price of the heat exchanger.